1. Field of the Invention
The present invention is related to an imaging device. More particularly, the present invention is related to an imaging device that enables obtainment of color images in a focused state regardless of the distance to a subject.
2. Description of the Related Art
An imaging device has been proposed, in which the point spread properties of an imaging lens optical system are intentionally expanded to a size that includes a plurality of pixels of imaging elements, while image reconstruction processes, that is, processes in which image signals are passed through reconstructing filters having properties inverse the blur properties of the imaging lens optical systems, are administered to enable obtainment of images in a focused state regardless of the distances to subjects. Japanese Unexamined Patent Publication No. 2009-089082 and E. R. Dowski, Jr. and W. T. Cathey, “Extended depth of field through wave-front coding”, Appl. Opt., Vol. 34, No. 11, pp. 1859-1866, 1995 describe examples of such an imaging device.
It is often the case that the aforementioned type of imaging device employs an imaging element constituted by a CCD or the like, similar to general imaging devices. In this case, a color imaging element, in which a color filter constituted by R (red), G (green), and B (blue) filters for each pixel arranged in a two dimensional matrix is provided on a photoelectric converting section, is often employed, to perform imaging of color images.
Japanese Unexamined Patent Publication No. 2009-089082 proposes to generate a reconstruction filter for data of each of R, Gr, Gb, and B channels, and employing the generated reconstruction filters to independently perform reconstruction processes for each channel, in the case that such a color imaging element is employed.
In the method described in Japanese Unexamined Patent Publication No. 2009-089082, convolution calculating processes, which have extremely high calculation costs, are administered for all pixels. Therefore, a problem is recognized that the calculation cost is high.